Dissolved Load: The Invisible Sediment Carried in Stream Water

The material a stream carries in chemical solution is called dissolved load (or solute load).

Composition

Primarily ions derived from mineral weathering:

• Cations: Ca²⁺, Mg²⁺, Na⁺, K⁺
• Anions: HCO₃⁻, SO₄²⁻, Cl⁻, NO₃⁻
• Silica (H₄SiO₄)

Importance

• Determines water chemistry (hardness, alkalinity, pH)
• Affects suitability for drinking, irrigation, industry
• Contributes to ocean salinity over geological time
• Used in geochemical tracing of water sources

Unlike suspended load (visible particles) or bedload (rolling grains), dissolved load is invisible but chemically significant.